function video_click(des) {
    document.getElementById('video_qt').style.display='block';
    document.getElementById('video_bj').style.display='block'
    document.getElementById("video_qt").innerHTML = '<iframe src="' + des + '" frameborder="0" width="100%" height="100%" scrolling="no" allowfullscreen="true" webkitallowfullscreen="true" mozallowfullscreen="true"></iframe>';
    document.documentElement.style.overflowY = 'hidden';
    document.body.style.overflowY = 'scroll';}
    function video_off(){
    document.getElementById('video_qt').style.display='none';
    document.getElementById('video_bj').style.display='none'
    document.getElementById("video_qt").innerHTML = '';
    document.documentElement.style.overflowY = '';
    document.body.style.overflowY = '';
}